Phytohormones and Biomolecules Produced by Trichoderma Strains as Eco-Friendly Alternative for Stimulation of Plant Growth

Abstract

The increase in agricultural food demand during the last years has caused the expansion of cultivated areas. As a result, more chemical fertilizers are used in agriculture to fulfill the demand of the increasing population worldwide. Pesticides and chemical fertilizers are not recommended because they lead to environmental pollution, the development of resistant pests, and cause serious health problems. Thus, the reduction in the use of synthetic products is highly recommended. In this regard, alternative strategies for sustainable agriculture should be implemented. One of these strategies is the use of biofertilizers, specifically biofertilizer fungi that are widely applied in agriculture. Trichoderma seems to be the best candidate for use in green technologies due to its wide biofertilization and biostimulatory potential. Most Trichoderma species increase nutrient availability and uptake in plants. They are considered as plant growth-promoting fungi (PGPF). This genus colonizes the root systems of plants and promotes their growth. It can increase nutrient availability and uptake in plants by fixing nitrogen and solubilizing phosphorus. Moreover, they help plants tolerate environmental stresses such as drought, salinity, and stimulate plant growth due to their capacity to produce phytohormones such as indole-3-acetic acid (IAA) and gibberellins (GAs). Phytohormones play an important role in agriculture; they enhance plant growth through several processes.